Pilot scale production of Hermetia illucens (L.) larvae and frass using former foodstuffs

Abstract

The food and feed sector requires new sustainable sources of protein and innovative solutions for upcycling of food waste (former foodstuffs), which today is downcycled into energy or even wasted. This study aimed at evaluating the use of former foodstuff waste streams as feed substrate for Hermetia illucens (L.) larvae (black soldier fly larvae, BSFL) under long-term and semi-industrial conditions. Different foodstuff-based mixtures and different stocking BSFL densities were used during 20 batches, and quality and safety assessments were performed on the main outputs, namely BSFL production performance, frass impurities, larval and frass nutrient profiles and heavy metal content. About 1400 kg of former foodstuffs (fresh weight) were used to produce 239 kg BSFL and 230 kg frass. The production of BSFL reared on former foodstuffs was highly efficient, with feed conversion rates (FCR) ranging between 2.3 and 5.5 (dry matter basis). The optimization experiment revealed that former foodstuffs-based mixture and high larval density (10 larvae/cm2) lead to highly efficient (FCR: 2.6) and heavy metal-free production of BSFL and frass. The quality of the derived BSFL meal was high in terms of protein and amino acids. Furthermore, the quality of the technical frass was high in terms of N, P, and K levels and minimal packaging material residuals (<2.65%). This investigation suggests that nutrients in former foodstuffs can be successfully and safely recycled in production of BSFL.